digilog.pk stocks a range of small lithium battery BMS protection boards for 1S, 2S, 3S, and 4S cell configurations — covering battery packs from 3.7V (single cell) up to 14.8V (4S). These compact boards protect cells from overcharge, over-discharge, and short circuit, and are ideal for DIY power banks, drone LiPo packs, small UPS systems, flashlights, RC toys, and portable electronics projects in Pakistan.
Why Use a Small Pack BMS?
- Cell protection — prevents overcharge above 4.2V/cell and over-discharge below 2.5–3.0V/cell
- Short circuit cutoff — protects both the battery and the load from wiring faults
- Balance charging — keeps all cells at equal voltage in 2S+ packs for long cycle life
- Compact form factor — small enough to fit inside portable device enclosures
Available Configurations
- 1S BMS — single-cell Li-ion protection; 3.0–4.2V; for flashlights and small devices
- 2S BMS — dual-cell pack; 6.0–8.4V; for small RC cars and compact power tools
- 3S BMS — 11.1V nominal; most popular for DIY power banks and medium drones
- 4S BMS — 14.8V nominal; for higher-voltage portable devices and LiFePO4 12V packs
Related Categories
Pair BMS boards with 18650 cells from Batteries & Chargers. Charge via TP4056 or balance charger from Battery & Charging. For larger packs see BMS Medium Pack (5S–13S). For all BMS types see BMS - Battery Management Systems.
Common Applications
- DIY power bank — 3S 18650 × 3 + 3S BMS + boost converter + USB output
- Drone LiPo protection — 3S or 4S BMS for DIY micro-drone battery
- Arduino/ESP32 battery pack — 1S or 2S with TP4056 charger and BMS for portable IoT nodes
- Flashlight battery — 1S BMS protecting a single 18650 cell
- RC car battery — 2S or 3S with appropriate C-rate BMS
How to Choose
- Match cell count exactly — a 3S BMS cannot be used with a 4S pack
- Current rating — choose BMS rated above your maximum load current; 5A for small devices, 20A+ for RC
- Chemistry — standard BMS for Li-ion/LiPo (4.2V cutoff); LiFePO4 BMS for LFP cells (3.65V cutoff)
- Balance function — always use a BMS with cell balancing for 2S+ packs
Learning Resources
- Cell Balancing — Battery University
- 18650 Battery Wiring — Random Nerd Tutorials
- BMS — Wikipedia — protection circuit overview and cell balancing methods
- 3S BMS Wiring Tutorials — YouTube
Need cells to pair with your BMS? Browse Batteries & Chargers. For larger battery systems see the full BMS collection. For bulk procurement contact info@digilog.pk.
